rust_tools: Fix the tool using real Rust uprev experiences.

Changes include bugs fixes, support running clean before compile
with ebuild command, and upload all tarballs (not just rustc).

BUG=chromium:1112551
TEST=unittest

Change-Id: I83a6845ba01590ea1319c90ebb427fb48c3da773
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2462042
Reviewed-by: Bob Haarman <inglorion@chromium.org>
Reviewed-by: George Burgess <gbiv@chromium.org>
Commit-Queue: Tiancong Wang <tcwang@google.com>
Tested-by: Tiancong Wang <tcwang@google.com>
2 files changed